Workers wear safety belts in high workplaces. To the safety belts, lanyards are connected. Hooks of the lanyards engage with structures, lifelines, or the like. Thus, even if a worker makes a misstep, falling from a high place is prevented. The safety belts enable prevention of falling accidents.
A work in a high place is performed, in a working range having some degree of width, by a worker moving in the range. A strap of the lanyard is made slack to some degree so as to allow movement in the working range. When the strap is very slack, the strap may be caught by a building. Further, if a worker makes a misstep, a falling distance may be increased by a distance corresponding to the slack. Therefore, the slack of the strap is preferably minimized. On the other hand, when the slack of the strap is too small, a worker is pulled by the lanyard during work. Working efficiency is reduced.
Lanyards including reels are used. The reel stores a strap of the lanyard. The strap can be extracted and wound. Further, reels including locking mechanisms are used. The locking mechanism regulates winding of a strap. The strap is wound by the reel, thereby reducing excessive slack of the strap. Further, an operation lever of the locking mechanism is operated, thereby preventing winding of the strap. A worker is less likely to be pulled by the lanyard during work. Thus, working efficiency is less likely to be reduced.
In the lanyard including the locking mechanism, unlocking operation and locking operation are performed when a workplace is changed. In the operations, the operation lever of the locking mechanism is operated. It is bothersome for a worker to frequently operate the operation lever.
In Japanese Examined Utility Model Publication No. 7-45234, a reel is suggested which includes a ratchet toothed member a portion of which is cut out in the circumferential direction, and a cam that engages with the ratchet toothed member. The reel is used for a lanyard. In the reel, the ratchet toothed member and the cam engage with each other to prevent winding of a strap. At a position where the portion of the ratchet toothed member is cut out, an engagement direction of the cam can be changed. At the position, the engagement direction is switched between a direction in which the cam engages with the ratchet toothed member and a direction in which the cam does not engage with the ratchet toothed member. When, at this position, the cam is switched to be oriented in the direction in which the cam does not engage with the ratchet toothed member, the strap can be wound.
In the reel, the ratchet toothed member contacts with the cam, whereby the ratchet toothed member supports the cam in such an orientation that the cam can be locked. In the orientation, the strap can be extracted. On the other hand, when the strap has been wound, the ratchet toothed member and the cam engage with each other, to prevent the winding. In order to cancel the prevention of the winding, the strap is extracted until the cam reaches the position at which the portion of the ratchet toothed member is cut out. At the position, the engagement direction of the cam is changed. The winding of the strap is started at this position.
The locking mechanism does not require an operation of a lever for operating the locking mechanism. When the strap is extracted by a worker, locking and unlocking operations for the locking mechanism are performed. The reel facilitates operation of the locking mechanism.